Add missing comma in .rockspec

nextfile-0.0.1-1.rockspec

@@ -11,7 +11,7 @@ description = {
 	detailed = [[
 	nextfile is a small Lua library for generating the next file in a sequence of files.
 	It was developed for use with tools that export sections of a video as images, and need to be able to name files sequentially without having generated all of the previous files themselves.
-	]]
+	]],
 	homepage = "https://themagician.cc/TheMagician/nextfile",
 	licence = "The Unlicence"
 }